As the most developed political organisation beyond the state, the EU has been regarded by many political theorists as indicative of a major shift towards post- and supranational forms of global governance, as well as offering a model for how such new political forms might be organised. However, as a growing number of political theorists have engaged more closely with the specifics of European integration and the operations of its institutions, these idealisations have largely fallen away. The process of European integration has been less straightforward and far more contested than has been often assumed, while the peculiar nature of the European political community and the uniquely complex organisation of its institutions have presented intriguing challenges to the core categories with which political theory operates. These concepts, which have been developed over the last centuries with the nation-state in mind as the primary example of modern political organization, cannot be applied wholesale to the EU. Concepts such as legitimacy, sovereignty, democracy, identity, citizenship, constitutionalism, representation, solidarity, etc. must be reassessed if they are to be useful for understanding and normatively scrutinising this political entity. This volume brings together some of the most important scholarly contributions over the last decades that have sought to contribute towards developing a political theory of the EU as an idiosyncratic political organisation. These contributions raise issues not only about the feasibility of attempts to construct political forms beyond the nation state, but also the extent to which they may be desirable. A mixed picture emerges from the state of the art: one that emphasises the existence and importance of continuities with the past in the development of international institutions on the one hand, and conceptual and practical innovations that point towards the need to break with the familiar on the other.

Centripetal democracy is the idea that legitimate democratic institutions set in motion forms of citizen practice and representative behaviour that serve as powerful drivers of political identity formation. Partisan modes of political representation in the context of multifaceted electoral and direct democratic voting opportunities are emphasised on this model. There is, however, a strain of thought predominant in political theory that doubts the democratic capacities of political systems constituted by multiple public spheres. This view is referred to as the lingua franca thesis on sustainable democratic systems (LFT). Inadequate democratic institutions and acute demands to divide the political system (through devolution or secession), are predicted by this thesis. By combining an original normative democratic theory with a comparative analysis of how Belgium and Switzerland have variously managed to sustain themselves as multilingual democracies, this book identifies the main institutional features of a democratically legitimate European Union and the conditions required to bring it about. Part One presents a novel theory of democratic legitimacy and political identity formation on which subsequent analyses are based. Part Two defines the EU as a demoi-cracy and provides a thorough democratic assessment of this political system. Part Three explains why Belgium has largely succumbed to the centrifugal logic predicted by the LFT, while Switzerland apparently defies this logic. Part Four presents a model of centripetal democracy for the EU, one that would greatly reduce its democratic deficit and ensure that this political system does not succumb to the centrifugal forces expected by the LFT.

European Union boundaries have always been unusual. In no other political community is both the prospect of enlargement and the ever-present possibility of withdrawal part of the constitutional framework. We find few other instances where some territories in a political community adopt a common currency while others do not. Examples of thick association agreements, such as we find between the EU and third countries like Switzerland and Norway, are uncommon. Over the last number of years, EU boundaries have been challenged like never before. Brexit poses a fundamental threat to the EU's territorial integrity and the rights of EU citizens to cross what have been regarded as open borders; the refugee crisis and the increase of terrorism both call into question the EU's ability to justly and effectively manage its external borders; the rise of populism is a direct challenge to internal free movement as the demand to reassert national borders becomes formidable; while the aftermath of the euro-crisis continues to put Monetary Union in doubt. By distinguishing between three categories of boundary change - boundary-making, boundary-crossing and boundary-unbundling - the authors in this volume attempt to shed light on the sustainability and legitimacy of Europe's boundaries in question. The chapters originally published as a special issue in the Journal of European Integration.